Cleansing compositions having antibacterial properties



Patented Oct. 26, 1954 ITION S HAVING ANTI- PROPERTIES Paul Lipsitz,Forest Brook Glen, DeL, assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware N Drawing.Application September 5, 1951,

, Serial No. 245,263

CLEANSING COMPOS BACTERIAL 4 Claims.

This invention relates to improved cleansing compositions, such as soapor synthetic detergents, characterized by possessing anti-bacterialproperties. It is an object of this invention to provide cleansingcompositions of the aforesaid types which are adapted for use both forlaundry and toilet purposes and which possess the quality of inhibitingbacterial growth without being irritating to the skin. Further objectsand achievements of this invention will appear as the descriptionproceeds.

While organic detergents such as soap and the so-called syntheticdetergents are capable of washing large quantities of bacteria and othermicro-organisms off surfaces, relatively appreciable numbers of suchorganisms are left on the surface which continue to multiply. In orderto remove these it is usually necessary to use a separate treatment withan anti-bacterial agent or disinfectant. A combined single stepprocedure would be highly desirable. However, the problem is not easy tosolve on a commercial scale in an economical manner inasmuch as soapdestroys the bactericidal efiicacy of nearly all disinfectants. In orderto be of universal application the bacteriostat must not lose itsactivity in the pres ence of soaps or synthetic detergents, it should beactive at low concentrations, it should be nontoxic to animals andnon-irritating to the skin and preferably should have some afiinity forthe skin and other surfaces so that after rinsing, a small amount willremain and exert a bacteriostatic effect.

Heretofore, several additives for soap have been proposed asbactericides such as sulfur, mercury compounds, phenols, chlorinatedphenols, etc. With some of these, high proportions of agent to soap arerequired to give the desired effect. Some of the compounds causeirritation to the skin. Others are toxic and present a hazard in use.Still others show no retention on the skin after rinsing, and the costof the more efiective ones is often so high as to restrict their use.

Now, according to my invention, disinfectant soaps and syntheticdetergents of high anti-bacterial activity, of good retentivity on theskin, and being non-toxic and non-irritating to the skin, may beobtained by incorporating into cleansing compositions of theaforementioned types an agent of the formula:

wherein R1 and R2 are the same or different alkyl radicals having notmore than a 2 C-atoms each, while N=Z is a radical of the group obtainedby removing 1 N-attached I-I-atom from ammonia, a primary or secondaryalkyl amine, morpholine and piperidine, the alkyl radicals in the saidalkyl amine containing not more than 4. C-atoms each. Following usage inthe literature, the above compounds may be designated as alkylderivatives of thiocarbamo-sulfenamides. They may be obtained byreacting an alkali metal salt of a dialkyl dithiocarbamic acid with theappropriate amine corresponding to the formula HN=Z, as above defined,in the presence of an oxidizing agent for instance iodine or sodiumhypochlorite.

It is remarkable that the above compounds exert bacteriostaticproperties in the presence of high concentrations of soap, consideringthat many related compounds which are known to possess anti-microbialactivity in the absence of soap, fail when admixed with the latter. Atthe same time, the agents of this invention have the additional qualityof being retained on the skin after the soap has been rinsed off,thereby continuing their bacteria-inhibiting activity for considerableperiods after their application.

The recommended concentrations of the bacteriostatic agent, for thepurpose of this invention, are from 0.5 to 5.0% by weight based on theWeight of the cleansing composition. They may be incorporated into thecleansing composition at any convenient stage during the manufacture ofthe latter. For instance, they may be added as a solid or as afinely-divided suspension in water or as a solution in a suitablesolvent, for example alcohol. In the case of soaps, they may be added inthe crutcher or in the plodder, if desired, when bar soaps are made. Inthe case of built soaps and synthetic detergents, which are spray dried,they may be added along with the builders (inorganic salts,carboxymethyl cellulose, etc.) immediately before spray drying. It isonly necessary that the anti-bacterial agent be dispersed completely anduniformly throughout the product.

The efi'ectiveness of the resulting product may be tested by standard orspecial tests, for instance, as follows: i

1. Test for dcti'uity.This is determined by preparing a standard soapsolution containing a standard, but small, concentration of the agent.Paper discs impregnated with the above: solution are placed on anagar-agar coated surface containing Staphylococcus aureus, and theactivity is gauged by the area of inhibited growth observed afterincubating for 24 hours.

2. Test for skin retentivity.-Pieces of untanned calf-skin are treatedwith the test solution described above and then (1) rinsed, (2) rinsedand washed, or (3) rinsed, washed and scoured withsoap. Thesepieces arethen placed on an agar-agar coated surface containing Staphylococcusaureas and observed after 24. hours of incubation. The area of inhibitedgrowth around each piece affords a qualitative measure of theretentivity of bacteriostatic agent by the skin after each of thementioned degrees of cleansing treatment.

Without limiting this invention, the following list of compounds isgiven as typical of the agents which may be used according tomyinvention.

3. NT,N-dimethyl-N ',N'-diethyl-thiocarbamo-sulfenamide,

(CH3) zN(]%-SN C 2H5) 2 s 4. N,Ndiethyl-thiocarbamo-sulfenamide,

c2115) ewe-satin 5. The compound obtained by condensing, by the aid ofiodine, N,N-dimethyl-dithiocarbamic acid and piperidine:

CH2CH2 6. The compound obtained by condensing, by the aid of iodine,N,N-dimethyl-dithiocarbamic acid and morpholine:

CH2CH2 '7. N,N,N',N tetraethyl thiocarbamo sulfenamide,

9. N,N-dim ethyl- N ,N -diisopropyl-thiocarbamosulfenamide,

U. S. P. 2,045,888,1Exam'ple 6. But, 'for the sake. of better clearness,the following "examples are" given to illustrate the method ofsynthesis.

A. 9.4 parts (0.05 mole) of sodium dimethyldithiocarbamate was dissolvedin parts of water and both this solution and 75 parts of a 5.25%solution of sodium hypochlorite dropped, with agitation, into 150 partsof concentrated aqueous ammonia. The temperature of theammonia was heldat 010 C. and when the addition was complete, the white precipitate wasfiltered ofi, washed with cold water, and dried. Its melting point wasfound to be at 69-70 C.

B. 4 parts (0.0213 mole) of sodium dimethyl dithiocarbamate wasdissolved in 17 parts of water and was addedto 35.2 parts of a 25%solution of dimethylamine. The mixture was kept at 20-25" C. and aniodine solution in aqueous potassium iodide was added dropwise withstirring overa period of 2 hours. Stirring was continued for 1 hours,and the precipitate was filtered, washed with water and dried. Afterrecrystallization from petroleum ether, the white product melted at48-51 C.

The above compounds were tested by me in compositions typified by thefollowing examples, with results as indicated.

Eacample 1.-Soap bar parts of soap powder (Ivory Snow) and 2 parts ofN,N-dimethyl thiocarbamo-sulfenamide were pulverized through amicromill, mixed thoroughly and the mixture pressed into molds at 7500p. s. i.

Tests made with a solution of the above composition containing 1 gram ofthe soap in 100 cc. of water showed excellent activity and re-, markablyhigh retentivity.

Example 2.Am'onic detergents 1 gram of a sodium alkyl-benzener-sulfonatedetergent containing in the alkyl radical an average of about 12 C-atomswas dissolved in 100 cc. of water, and then .020 grams ofN,N,N',N'-tetramethyl thiocarbamosulfenamide were added.

Example 3.-Nonionic detergents The detergent in this case was a mixtureof compounds obtained by condensing a long-chain alcohol with an averageof 16 to 18 moles of ethylene oxide. 100 grams of a 1% solution of thisdetergent water were treatedwithZ grams of the agent named in Example 2.

Example 4.C'ationic detergents It will be clear that my inventionprovides.

novel cleansingcompositions of great practical;

and economic value. They may be used in all instances where separatesteps of'washing and then disinfecting have been used heretofore.

Thus, the laundering of hospital supplies, the

cleaning of hospital floors and walls, the cleaning of dairies includingthe barns and the milk-proo essing buidings, the washing of bottleswhich are to contain foodstuffs, the washing of dishes in restaurantsand hotels, the cleaning of oflice buildings, the cleaning oflavatoriesin public buildings and a myriad of similar applications are carried outwith simultaneous disinfection thereof. Also, disinfection can beaccomplished simultaneously with washing where it normally is not donebecause of the necessity for a separate treatment such as in toilet soapfor personal use, the home laundry, home cleaning and scrubbing, etc. Itis also useful for physicians, nurses, and veterinaries in that washingthe hands simultaneously disinfects them and leaves a bacteriostaticresidue retained on the skin.

Many other variations in the details of this invention will be readilyapparent to those skilled in the art.

I claim as my invention:

1. A cleansing composition comprising soap and an anti-bacterial agentrepresented by the formula:

/N-(|JSN=Z R2 wherein R1 and R2 are alkyl radicals of not over 2 C-atomseach, while N=Z represents a radical of the group obtained by removingone N-attached H-atom from ammonia, primary and secondary alkyl amineshaving not more than 4 C-atoms in each alkyl radical, morpholine andpiperidine.

2. A cleansing composition as in claim 1, the anti-bacterial agent beingpresent in the propor tion of 0.5 to 5.0% by Weight based on the Weightof the cleansing composition.

3. A cleansing composition as in claim 1, the anti-bacterial agent beingN,N-dimethyl-thiocarbamo-sulfenamide.

4. A bacteriostatic cleansing composition comprising soap andN,N-dimethyl-thiocarbamosulfenamide, the proportion of the latter beingfrom 0.5 to 5.0% by Weight of the entire composition.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 22,750 Tisdale et a1 Apr. 30, 1946 2,353,735 Kunz et alJuly 18, 1944

1. A CLEANSING COMPOSITION COMPRISING SOAP AND AN ANTI-BACTERIAL AGENTREPRESENTED BY THE FORMULA: